Medicare, Medicaid, Life and Health Insurance/insurance approval

QuestionMy daughter has Medicare and a supplement (WEllCARE). She has been going to Physical Therapy on her feet. They billed Medicare instead of WellCare and as a result of not getting paid they cancelled all her therapy sessions over a week ago. They said they would get in touch with me when they got an answer. My question is: What's the hold up? How long does it take for an insurance company to say 'yes, I'll pay or no I won't'?

AnswerIsn't Wellcare a Medicare Advantage plan. I am not familiar with it but when I Googled that is what I found. If it is a Medical policy they won't pay if Medicare doesn't pay but I need more info to help you.
Has she exceeded the Medicare cap of $1920 for the year. Why did the plan deny the claim?